On Fri, Mar 15, 2019 at 12:25:22PM +0100, Antoine Pitrou wrote: > Yeah, well.... I do think "+=" for lists was a mistake. I *still* have > trouble remembering the exact difference between "list +=" and > "list.extend" (yes, there is one: one accepts more types than the > other... which one it is, and why, I never remember;
Both accept arbitrary iterables, and the documentation suggests that they are the same: https://docs.python.org/3/library/stdtypes.html#mutable-sequence-types Perhaps you are thinking of the difference between list + list versus list += iterable? [...] > There is a virtue to > > """There should be one-- and preferably only one --obvious way to do > it""" "It" here refers to two different things: "I want to update a dict in place": The Obvious Way is to use the update method; the fact that += works as well is just a side-effect of the way augmented assignments are defined. "I want a new dict that merges two existing dicts": The Obvious Way is to use the merge operator (possibly spelled + but that's not written in stone yet). -- Steven _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
